In the prior art, it has been customary for the carpenter on the job site to form the intersecting lockset cross bore and bolt receiving edge bore in the door panel at the desired height above the floor and with the cross bore at a precise distance from the swinging edge of the door. Without this precision, the components of the lockset will not be properly received and the lock will not operate properly. This customary precedure in the field has required the carpenter to utilize expensive boring jibs and special size drilling bits.
The problem becomes more difficult when the cross bore and edge bore must be formed in a metal clad or metal skinned foam-filled door utilizing 24 gauge steel sheets for the opposite side skins.
The present invention has been devised to deal with and simplify the above prior art problems incident to the formation of lockset cross bores and edge bores in doors. In the invention, the door metal skins are accurately prepunched in the manufacturing process to establish a well located cross bore axis and a very clean appearance. At an appropriate time in the manufacturing process of the door, the required bolt receiving edge bore is formed accurately in the wooden stile at the swinging edge of the door in proper intersecting relationship with the axis of the larger cross bore. In a more primative state of development of the invention, a cardboard sleeve or dam was inserted between the metal skins to block the flow of urethane foam into and through the bores during the subsequent foaming procedure.
In the completed invention according to the present application the cardboard sleeve or dam is eliminated along with the necessity for drilling the stile edge bore through this sleeve for proper lock installation. Instead, after formation of the punched openings in the metal skins and the intersecting edge bore in the stile, a single unitary molded plastic liner or dam for both intersecting bores is installed prior to the final assembly and foaming operations, this liner having accurate dimensions for registration with the punched openings of the metal skins and for snug entry into the edge bore of the wooden stile. The liner or dam which is molded from plastic has integral annular sealing lips at the opposite ends of its cross bore portion to effectively seal with the interior faces of the metal skins so that no foam can enter or pass through either of the critical right angular bores of the liner which intersect and are in open communication. No drilling or cutting of the liner is required as was the case with the primative cardboard sleeve and no job site drilling of doors by carpenters with expensive jigs and tools is required by virtue of the invention. Economy is greatly enhanced as well as convenience both in the manufacturing of doors and in their installation compared to the prior art practices.
Another major benefit of the invention is that the main cross bore sleeve abuts the opposite side sheet metal door skins and reinforces them against buckling during the installation of the lock hardware.
Examples of the patented prior art are shown in the following U.S. patents: U.S. Pat. No. 2,924,861 U.S. Pat. No. 3,039,291 U.S. Pat. No. 3,060,523 U.S. Pat. No. 3,287,855 U.S. Pat. No. 3,359,699 U.S. Pat. No. 3,455,078 U.S. Pat. No. 3,512,305 U.S. Pat. No. 3,987,600 U.S. Pat. No. 4,044,511.